1. Field of the Invention
The present invention relates to the field of heat dissipation, and in particular to a heat dissipation pipe loop and a backlight module using the heat dissipation pipe loop.
2. The Related Arts
Liquid crystal displays (LCDs) have a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and are thus of wide applications. Most of the liquid crystal displays that are currently available in the market are backlighting liquid crystal displays, which comprise a liquid crystal display panel and a backlight module. The operation principle of the liquid crystal display panel is that, with liquid crystal molecules interposed between two parallel glass substrates, a plurality of vertical and horizontal tiny wires is arranged between the two glass substrates and application of electricity is selectively made to control the liquid crystal molecules to change direction in order to refract out light emitting from the backlight module for generating images. Since the liquid crystal panel itself does not emit light, light must be provided by the backlight module in order to normally display images. Thus, the backlight module is one of the key components of a liquid crystal display. The backlight modules can be classified in two types, namely a side-edge backlight module and a direct backlight module, according to the position where light gets incident. The direct backlight module comprises a light emission source, which is arranged at the backside of the liquid crystal display panel to form a planar light source directly supplied to the liquid crystal display panel. The side-edge backlight module comprises a light emission source, which is arranged at an edge of a backplane to be located rearward of one side of the liquid crystal display panel. The light emitting from the light emission source enters a light guide plate (LGP) through a light incident face at one side of the light guide plate and is projected out of a light exit face of the light guide plate, after being reflected and diffused, to pass through an optic film assembly to form a planar light source for the liquid crystal display panel.
Heretofore, commonly used light emission sources include a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), and a light-emitting diode (LED), among which the LED is advantageous in respect of environmental conservation and extended life span and is thus widely used. A heat dissipation device that is provided for dissipation of heat from the LED is a vital part for the purposes of preventing the backlight module from getting deteriorated and extending the life span of the backlight module.
In the state of the art, it is common to arrange a heat dissipation pipe loop under a printed circuit board (PCB) on which a plurality of LED lights is mounted in order to achieve heat dissipation of the LED lights.
Referring to FIG. 1, which is a schematic view showing a conventional LED heat dissipation pipe loop, the pipe loop is composed of alloy pipes made of a metal, such as copper and titanium and comprises a liquid pipe 100, an evaporator section 300, a gas pipe 500, and a condenser pipe 700. The heat dissipation pipe loop is filled with a heat dissipation liquid that can readily evaporate through absorption of heat (including water, Freon refrigerant, ammonia, and methanol). The heat dissipation liquid passes through the liquid pipe 100 into the evaporator section 300 to absorb heat and evaporate into a gas that enters the gas pipe 500 and passes through the condenser pipe 70 to get condensed into liquid for entering the liquid pipe 100 against. This cycle is repeated to enhance the heat dissipation effect.
Although the heat dissipation pipe loop of such an arrangement achieves a bettered effect of heat dissipation, installation of a greater number of heat dissipation pipe loops is required for a backlight module including an increased number of LED lights from which heat is to be dissipated.
Referring to FIG. 2, a schematic view is given to show conventional installation of an LED heat dissipation pipe loop. A regular side-edge backlight module comprises two sets of backlight source 900 that are arranged opposite to each other. Each backlight source 900 comprises a printed circuit board 902 and a plurality of LED lights 904 mounted on the printed circuit board 902. Thus, four identical heat dissipation pipe loops are adopted in such an arrangement of backlight module to dissipate heat. Two of the heat dissipation pipe loops are arranged under each of the printed circuit boards 902 for dissipating heat from the LED lights thereof. In installation, the printed circuit boards 902 are positioned against evaporator sections 300 of the heat dissipation pipe loops.
Thus, such an arrangement of the heat dissipation pipe loop requires an increased number of heat dissipation components to be used in the backlight module, thereby increasing the cost of heat dissipation and the cost of manufacture, and also complicating the assembling operation.